1. Field of the Invention
This invention relates in general to computer-implemented database management systems, and, in particular, to an object-oriented framework for managing access control to a multimedia database.
2. Description of Related Art
For nearly half a century computers have been used by businesses to manage information such as numbers and text, mainly in the form of coded data. However, business data represents only a small part of the world""s information. As storage, communication and information processing technologies advance, and as their costs come down, it becomes more feasible to digitize other various types of data, store large volumes of it, and be able to distribute it on demand to users at their place of business or home.
New digitization technologies have emerged in the last decade to digitize images, audio, and video, giving birth to a new type of digital multimedia information. These multimedia objects are quite different from the business data that computers managed in the past, and often require more advanced information management system infrastructures with new capabilities. Such systems are often called xe2x80x9cdigital libraries.xe2x80x9d
Bringing new digital technologies can do much more than just replace physical objects with their electronic representation. It enables instant access to information; supports fast, accurate, and powerful search mechanisms; provides, new xe2x80x9cexperientialxe2x80x9d (i.e. virtual reality) user interfaces; and implements new ways of protecting the rights of information owners. These properties make digital library solutions even more attractive and acceptable not only to corporate IS organizations, but to the information owners, publishers and service providers.
Generally, business data is created by a business process (an airline ticket reservation, a deposit at the bank, and a claim processing at an insurance company are examples). Most of these processes have been automated by computers and produce business data in digital form (text and numbers). Therefore it is usually structured coded data. Multimedia data, on the contrary, cannot be fully pre-structured (its use is not fully predictable) because it is the result of the creation of a human being or the digitization of an object of the real world (x-rays, geophysical mapping, etc.) rather than a computer algorithm.
The average size of business data in digital form is relatively small. A banking recordxe2x80x94including a customers name, address, phone number, account number, balance, etc.xe2x80x94represents at most a few hundred characters, i.e. few hundreds/thousands of bits. The digitization of multimedia information (image, audio, video) produces a large set of bits called an xe2x80x9cobjectxe2x80x9d or xe2x80x9cblobsxe2x80x9d (Binary Large Objects). For example, a digitized image of the parchments from the Vatican Library takes as much as the equivalent of 30 million characters (30 MB) to be stored. The digitization of a movie, even after compression, may take as much as the equivalent of several billions of characters (3-4 GB) to be stored.
Multimedia information is typically stored as much larger objects, ever increasing in quantity and therefore requiring special storage mechanisms. Classical business computer systems have not been designed to directly store such large objects. Specialized storage technologies may be required for certain types of information, e.g. media streamers for video or music. Because certain multimedia information needs to be preserved xe2x80x9cforeverxe2x80x9d it also requires special storage management functions providing automated back-up and migration to new storage technologies as they become available and as old technologies become obsolete.
Finally, for performance reasons, the multimedia data is often placed in the proximity of the users with the system supporting multiple distributed object servers. This often requires a logical separation between applications, indices, and data to ensure independence from any changes in the location of the data.
In a digital library (DL), the multimedia object can be linked with the associated indexing information, since both are available in digital form. Integration of this legacy catalog information with the digitized object is crucial and is one of the great advantages of digital library technology. Different types of objects can be categorized differently as appropriate for each object type. Existing standards like MARC records for libraries, Finding Aids for archiving of special collections, etc. can be used when appropriate.
Object-oriented approaches are generally better suited for such complex data management. The term xe2x80x9cobject-orientedxe2x80x9d refers to a software design method which uses xe2x80x9cclassesxe2x80x9d and xe2x80x9cobjectsxe2x80x9d to model abstract or real objects. An xe2x80x9cobjectxe2x80x9d is the main building block of object-oriented programming, and is a programming unit which has both data and functionality (i.e., xe2x80x9cmethodsxe2x80x9d). A xe2x80x9cclassxe2x80x9d defines the implementation of a particular kind of object, the variables and methods it uses, and the parent class it belongs to.
Controlling access to digital libraries and other types of multimedia databases by multiple users is an important aspect of managing the distribution of contents in a multimedia database. Currently, access control support has been problematic and of limited capability. An example of one such access control support is the access control provided for the DB2 Digital Library, a product from International Business Machines Corporation of Armonk, N.Y. The DB2 Digital Library provides two ways in which the user can provide access control. First, the DB2 Digital Library product includes a ready-to-use Java system administration tool. However, this Java system administration tool has a limited number of functions and is thus unacceptable for many sophisticated users. The DB2 Digital Library product also provides a low-level set of C Application Programming Interfaces (APIs) from which users can develop customized access control. However, these low-level APIs have three deficiencies. First, they are difficult to use for novice users. Second, they provide only limited functionalities and cannot meet the expectation of today""s demanding application programers. Finally, these low level C APIs have no corresponding higher level APIs to allow for better interoperability.
Accordingly, there is a need in the art for an object-oriented framework for managing access control in a multimedia database which provides better usability, an expanded and more sophisticated capability, and increased interoperability.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a method, apparatus, and article of manufacture for an object-oriented framework for managing access control in a multimedia database.
In accordance with the present invention, a technique for controlling access to a datastore connected to a computer is provided. Initially, a datastore access control object is generated for the datastore. The datastore access control object enables controlling access to the datastore by manipulating an access control list object to set access privileges.